Chapter 3 (Book) Part I Flashcards
3 domains
bacteria
eukaryotes
archaea
bacterial cells are remarkable for their ______ size and ________ growth
small, efficient
bacteria coordinate DNA replication through 2 things
DNA replisome
cell fission ring
3 overall tasks of cells
outcompete others for nutrients
protect itself from toxins/predators
reproduce
bacateria share 3 traits
thick, complex outer envelope
compact genome
tightly coordinated cell functions
what does the outer envelope of a bacteria do
protection from environmental stress
mediates exchange with the environment
compact genome of bacteria
relatively little noncoding DNA
maximize production of cells from limited resources
purpose of tightly coordinated functions
may allow for a high reproduction rate
are archaea prokaryotes?
yes
what 2 uniquely adapted structures do archaea have that allow them to survive in extreme environments
membrane
envelope
do eukaryotic cells have a nucleus and membranous organelles?
yes
which organelles evolved by endosymbiosis with engulfed bacteria?
mitochondria
chloroplasts
both in eukaryotic cells
membrane/envelope layer oder of E. coli from outside to inside
lipopolysaccharide (LPS) –> outer membrane –> cell wall –> periplasm –> inner membrane (cell membrane)
what does the cytoplasm contain and what is it like
gel-like network
contains proteins and macromolecules
enclosed by a cell membrane
in Gram-neg bacteria, what is the cell membrane called
the “inner membrane” to distinguish it from the additional outer membrane
what is the inner membrane composed on
phospholipids
transporter proteins
other molecules
what does the inner membrane do
prevent cytoplasmic proteins from escaping
maintain ion/nutrient gradients
where is the cell wall
between inner and outer membranes
what is the call wall, what does it do
a cage-like structure made of polysaccharides covalently linked by peptidoglycan
forms a single molecule surrounding the cell
limits expansion of cytoplasm to keep the cell membrane intact when water flows in
resulting turgor pressure from the cell wall makes the cell _____
rigid
periplasm
aqueous layer containing proteins
ex. sugar-binding proteins
what is the outer membrane made of
phospholipids and LPS
lipopolysaccharide
class of lipid attached to long polysaccharide chains
the LPS layer may be surrounded by a thick ______
capsule
slippery mucous layer that inhibits phagocytosis by macrophages
what 2 structures make up the envelope
cell wall
outer membrane
does the envelope have the cell-surface proteins that allow the bacteria to interact with host organisms?
yes
ex. E. coli cell-surface proteins help it colonize human intestinal epithelium
flagellum
helical protein filament
has a rotary motor that propels the cell to search for a better environment
what provides internal attachment points for 1+ chromosomes
cell membrane/cell envelope
nucleoid
a system of looped coils of chromosome
located in cytoplasm
not membrane-bound
sequence of turning DNA –> protein
DNA from nucleoid transcribed by RNA polymerase to mRNA, tRNA, rRNA
mRNA transcripts bind ribosomes (polyribosomes) to start synthesizing proteins
chaperones (protein complex) helps proteins fold into the right conformation
what is a limitation of cell fractionation
doesn’t provide info about the processes of an intact cell
what is genetic analysis
make a mutant strain that doesn’t function right
the phenotype of the mutant gives clues about the function of the altered part
4 common chemical components shared by all cells
water
essential ions
small organic molecules
macromolecules
water is the fundamental _______ of life
solvent
3 essential ions
potassium
magnesium
chloride ions
what are small organic molecules
lipids and sugars that are in membranes and provide nutrition by catabolism (breakdown)
macromolecules
nucleic acids and proteins
contain info, catalyze rxns, mediate transport
cell composition varies with what 3 things
species
growth phase
environmental conditions
relative biochemical composition
70% water
16% protein
6% RNA
3% phospholipids
polyamine
organic cation with multiple amine groups
balance neg charge of DNA and stabilize ribosomes during translation
protenome
proteins expressed by a cell under given conditions
2D PAGE
separate cell contents by pH
separate cell by size
what are examples of the most highly expressed proteins
ribosomes
translation factors
outer memb proteins
why is high nucleic acid content (8% in E. coli) advantageous for microbes
allows the cell to maximize reproduction of its chromosome
minimizing resources for protein-rich cytoplasm
peptidoglycan
organic polymer of peptide-linked sugars
1% of cell mass
found in bacterial cell wall
what does 1% investment of cell mass toward peptidoglycan mean
importance of maintaining turgor pressure in dilute environments (cell wall)
otherwise water would enter by osmosis and cause osmotic shock
2 functions of cell membrane
contain cytoplasm and mediate transport
has proteins with specific functions like enzymes and signal receptors
most membrane lipids are __________
phospholipids
charged phosphate head on outside of bilayer
hydrophobic tail on inside of bilayer
phospholipid structure
glycerol with ester links to 2 FA
negative phosphoryl polar head
4 functions of membrane proteins
structural support
signal reception
secretion of virulence factors and communication signals
ion transport / energy storage
structural membrane proteins 3 functions
anchor layers of the cell envelope
attach to cytoskeleton
secure flagella
secretory membrane proteins
complexes export toxins and signals across the envelope
transport membrane proteins
maintain ion gradients
what molecules can passively diffuse
O2, CO2, H2O
small uncharged molecules
most cells maintain a concentration of total solutes that is higher ______ the cell than _______
inside, outside
osmosis
water moving from purest water (least solutes) to impure areas (most solutes)
osmotic pressure
pressure on the cell membrane from the influx of water
can burst/lyse the cell
penicillin does this
membrane-permanent weak acids and bases
cross the membrane in uncharged form and reduce acid or alkali stress
ion gradient
can store energy for nutrition or drive transport of other molecules
cardiolipin and environmental stress
a membrane phosphatidate that increases in bacteria in response to starvation
accumulates in patches and bind stress proteins like transporters for osmoprotectants if the cell is under osmotic stress
cholesterol is found in ________ and ________ are found in bacteria
eukaryotes, hopanoids
both are still and reinforce the membrane
why are archaeal membranes unique
no ester bonds, instead have ether bonds which are more stable
have isoprene hydrocarbon chains (terprenoids)
